Bank windows (used to) work after you initialized them by opening a bank session once. Might be changed, my info is quite outdated.
The arguments for bag close are the bag IDs, something like
/bag_close -3 256 (might be a comma between the two numbers, I forget), same as the numbers used for the /show_window thing. Yes, the IDs are always the same. If you check the default ProfitUI uisettings I left some comments in there grouping the bags by type, useful to get the IDs of those you need.